Curved surfaces are used in a number of applications including but not limited to doubly curved crystals for x-ray applications, mirrors for ring laser gyros, and substrates for single or multilayer thin films.
Doubly curved crystals are known to be useful as a focusing device for monochromatic x-ray or a wavelength dispersive device in an x-ray spectrometer. For example, a toroidal curved crystal can provide point-to-point focusing of monochromatic x-rays, and a crystal curved to an ellipsoid can be used as a broad energy x-ray detection device. Some of the prior art is described in U.S. Pat. No. 4,780,899 and U.S. Pat. No. 4,949,367. These devices, having crystals bonded on a smooth concave substrate by a very thin layer of adhesive, have the drawback that the smoothness of the crystal planes is strongly affected by irregularities of the bonding layer. The irregularities can result from the lack of initial uniformity of the bonding layer on the substrate, or can occur during mounting of the crystal even if the initial adhesive layer is highly uniform. Another drawback is that a carefully prepared substrate is required for each curved surface.
Thus, the present invention is directed to providing inexpensive high quality optical surfaces, and to methods of fabrication thereof.